When Peter Green left Fleetwood Mac in early 1970, it wasn’t clear how the band would move forward. Not only was Green one of Mac’s lead singers and primary songwriters, he was an avatar for their creative spirit: A ripping blues guitarist who was also a sensitive mystic—a musician who honored tradition without rejecting progress. As Mick Fleetwood later put it, losing him was like taking the rudder off a sailboat: You won’t sink, but good luck getting anywhere. Named for the country commune where the band regrouped, 1970’s Kiln House isn’t as intense as the Green-era albums, but it has a sense of delicacy and play that hint at where they’d go as the decade wore on. This version of Fleetwood Mac could be bluesy, but without the volcanic testosterone of hard rock (“Tell Me All the Things You Do”). And the band could be folksy, but more for the sake of gentleness than anachronism or historical credibility (“Mission Bell”). As for the extensive guitar playing on Kiln House: Jeremy Spencer’s leads—“This is a Rock” and “Hi Ho Silver,” especially—send up early rock ’n’ roll as well as any late-Beatles Paul McCartney, while Danny Kirwan’s work recasts the band’s blues roots as, if not easy listening, then something closer to early-1970s Grateful Dead than mid-1960s Cream (“Station Man”). You could say the middle of the road is the best place to get hit. But listen to the temperance and steadiness of Kiln House, and you might start to hear it as the only real way to move forward.